Cost of Lunar Aluminium

Ok, the cheapness of lunar produced aluminum and solar panels
compared to those launched from Earth has been talked about here
many-many times, so I decided to do some calculations. Unfortunately
I don't have all the data I want, so I'm starting off with a much
simplified model that gives an overly *optimistic* scenario. As
launch costs arte likely to vary over time, the calculations will be
in terms of mass fraction after contiuosly running the plant for 30
years and "break-even" operation time. Similarily, as it is not
known how much energy going from lunar regolith is going to consume
(including recovery and recycling of any imported consumables) so
a number of scenarious is considered.

The calculations are only for production of aluminium, and all
suggestions how to acheive more accurate formulas are welcome.

The assumptiums used a
* only the mass of solar batteries is considered
* the batteries provide continuous 24h power
* leap years are not accounted for
* all the batteries are transported to moon
* the aluminum will be consumed on moon and not launched
to earth orbit, as that makes 'launched from earth'
aluminum chaper and 'made on moon' aluminum more expensive
* the power output of the batteries does not degrade over time

Presently, producing 1 kg of aluminium from alumina costs 16KW/h
down here on Earth. Assuming that to be the best possible case
(even if extremely optimistic) of converting regolith to aluminum,
and considering a number of small multiplies the break-even time
and mass fraction for 30 year opertaion a

KWh/kg(Al) 100 150 200 250 300 Battery W/kg

16000 18.26 12.18 9.13 7.31 6.09 years
0.61 0.41 0.3 0.24 0.2 kg
24000 27.4 18.26 13.7 10.96 9.13 years
0.91 0.61 0.46 0.37 0.3 kg
32000 36.53 24.53 18.26 14.61 12.18 years
1.22 0.81 0.61 0.49 0.41 kg
40000 45.66 30.44 22.83 18.26 15.22 years
1.52 1.01 0.76 0.61 0.51 kg
48000 54.79 36.53 27.4 21.92 18.26 years
1.83 1.22 0.91 0.73 0.61 kg

As the model is not affected by launch costs, it would appear that
using present technology aluminum produced on the Moon would not
be cheaper - or at the very least signifcantly cheaper - than that
launched from Earth.

--
Sander

+++ Out of cheese error +++

Sander Vesik wrote:

Presently, producing 1 kg of aluminium from alumina costs 16KWh

all fine so far...

down here on Earth. Assuming that to be the best possible case
(even if extremely optimistic) of converting regolith to aluminum,
and considering a number of small multiplies the break-even time
and mass fraction for 30 year opertaion a

KWh/kg(Al) 100 150 200 250 300 Battery W/kg

16000 18.26 12.18 9.13 7.31 6.09 years

And here all goes down the drain due to mixing watts and kilowatts

The numbers are still correct, except *instead* of showing break-even
they show the cost level of 1 ton of lunar aluminium = launching 1kg
to Moon from Earth. Which is still an interesting number.

Crap, shouldn't post when i'm sleepy.

--
Sander

+++ Out of cheese error +++

"Sander Vesik" wrote in message
...
Ok, the cheapness of lunar produced aluminum and solar panels
compared to those launched from Earth has been talked about here
many-many times, so I decided to do some calculations.

You provided numbers for aluminum. I was wondering about solar panels. If
we can make those on the moon, then it becomes much easier to make aluminum,
oxygen, and other things. If we can reach break even with machines running
40% of the time, that would be good.

Mike Rhino wrote:
|"Sander Vesik" wrote in message
...
| Ok, the cheapness of lunar produced aluminum and solar panels
| compared to those launched from Earth has been talked about here
| many-many times, so I decided to do some calculations.
|
|You provided numbers for aluminum. I was wondering about solar panels. If
|we can make those on the moon, then it becomes much easier to make aluminum,
|oxygen, and other things. If we can reach break even with machines running
|40% of the time, that would be good.

Aluminum panels are good, but what about fiberglass? Can't silica
be heated and spun into fiberglass? As soon as you have a spool of
the stuff, it is pretty easy to weave it into great big blankets of
fiberglass. And the blankets could be as big as you wanted them to
be, both flexible and pliant, even more useful than sheets of aluminum.
Finally, if you are worried about filtration systems, blankets of
fiberglass can be woven with pores that are just the right size. And
finally, if you wanted fiberglass panels that are absolutely air-tight,
just spray the thing over with a highly liquefied glass.

"Mike Rhino" wrote in message
...

You provided numbers for aluminum. I was wondering about
solar panels. If we can make those on the moon, then it
becomes much easier to make aluminum, oxygen, and other
things. If we can reach break even with machines running
40% of the time, that would be good.


If memory serves aluminium production requires fairly continuous power.
I favour a solar thermal approach for this scale and application. A
large mirror heating an area of regolith which then powers a gas/steam
turbine continuously through out the Lunar day and night. This should
be a much cheaper system than nuclear or solar cells.

Pete.

In article ,
Matthew Montchalin wrote:
Aluminum panels are good, but what about fiberglass? Can't silica
be heated and spun into fiberglass?

Kind of. Pure silica is not very cooperative; you need to add other
materials to get a well-behaved glass. Most ordinary glass on Earth is
soda-lime glass, with sizable amounts of sodium oxide and calcium oxide
making the silica more tractable.

Moreover, there is not a lot of silica in lunar rocks -- metal silicates,
yes, but straight silica is fairly rare.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

"Sander Vesik" wrote in message
...
Sander Vesik wrote:

Presently, producing 1 kg of aluminium from alumina costs 16KWh

all fine so far...

down here on Earth. Assuming that to be the best possible case
(even if extremely optimistic) of converting regolith to aluminum,
and considering a number of small multiplies the break-even time
and mass fraction for 30 year opertaion a

KWh/kg(Al) 100 150 200 250 300 Battery W/kg

16000 18.26 12.18 9.13 7.31 6.09 years

And here all goes down the drain due to mixing watts and kilowatts

The numbers are still correct, except *instead* of showing break-even
they show the cost level of 1 ton of lunar aluminium = launching 1kg
to Moon from Earth. Which is still an interesting number.

Not doubting your figures, but why send aluminium back to Earth? I would
think it better to send high-value items (finished goods).


--
Alan Erskine
We can get people to the Moon in five years,
not the fifteen GWB proposes.
Give NASA a real challenge

Henry Spencer wrote:
|Matthew Montchalin wrote:
|Aluminum panels are good, but what about fiberglass? Can't silica
|be heated and spun into fiberglass?
|
|Kind of. Pure silica is not very cooperative; you need to add other
|materials to get a well-behaved glass. Most ordinary glass on Earth is
|soda-lime glass, with sizable amounts of sodium oxide and calcium oxide
|making the silica more tractable.
|
|Moreover, there is not a lot of silica in lunar rocks -- metal silicates,
|yes, but straight silica is fairly rare.

After the metals are extracted, wouldn't there be some kind of silica
left over, suitable for spinning into fiberglass? I was hoping that
the usual method for operating a foundry would be by inducing an
electrical charge across the resistance of a vacuum, and sand or rock
that falls into that area would be converted into a plasma of some
kind that could be rotated in a magnetic field somehow, allowing the
metals to be removed from the silica?

I'm not a chemist, just trying to look at this like any other ordinary
person does; that is why I expect the earth to be shipping up the
following items for the first lunar production facility, in this order:

communications beacon
nuclear reactor + solar panels
mini-habitat for temporary lodging
titanium or aluminum poles and panels for putting beacon on a tower
lightweight cables for use as electrical conductors and connecting towers
flywheels for kinetic power management and conversions

Get that stuff in place first, and the next thing you know, miniature
bulldozers could be sent up for shoving sand up ramps and dropping the
stuff into an electrical forge of some kind (both of which are not
even on the list yet).

"Matthew Montchalin" wrote in message
...

I'm not a chemist, just trying to look at this like any other ordinary
person does; that is why I expect the earth to be shipping up the
following items for the first lunar production facility, in this order:

communications beacon
nuclear reactor + solar panels
mini-habitat for temporary lodging
titanium or aluminum poles and panels for putting beacon on a tower
lightweight cables for use as electrical conductors and connecting
towers
flywheels for kinetic power management and conversions

Would a habitat be useful for this purpose, or would it simply be an extra
expense? A habitat all by itself is totally useless. In order for humans
to do useful work, they'll need tools, a lab, and a garage. There is useful
work for humans to do, such as examine rocks in a lab or repair vehicles.
There is a risk that we'll spend twice as much for 30% more work.

Mike Rhino wrote:
|"Matthew Montchalin" wrote in message
...
|
| I'm not a chemist, just trying to look at this like any other ordinary
| person does; that is why I expect the earth to be shipping up the
| following items for the first lunar production facility, in this order:
|
| communications beacon
| nuclear reactor + solar panels
| mini-habitat for temporary lodging
| titanium or aluminum poles and panels for putting beacon on a tower
| lightweight cables for use as electrical conductors and connecting towers
| flywheels for kinetic power management and conversions
|
|Would a habitat be useful for this purpose, or would it simply be an extra
|expense?

Somebody's got to raise up those radio towers and rig the power lines,
and the temporary habitats can always be expanded later on, or disassembled
and used for other purposes. The temporary habitats might at first be
no bigger than the Lunar Lander was.

|A habitat all by itself is totally useless.

*Anything* all by itself is useless, that's why we keep sending stuff
up into the same general area. The need for a tower is so that we
don't overshoot the area. We can land in the same general area, over
and over again, with more reliability and accuracy, the more stuff
we keep deploying.

Even if have a dozen Lunar Rovers on the Moon, it makes it a lot easier
travelling 5 kilometers if we have a tower to aim for. We need a place
to drop supplies, and the stuff has to go in one particular place so
we don't spend precious time trying to figure out where it all landed.

|In order for humans to do useful work, they'll need tools, a lab, and a
|garage.

If you need a roof over the mini-habitat, you can unroll a big aluminum
blanket, or a sheet of mylar, and position it on poles. It would be nice
if the blanket were photovoltaic in nature, because that way you could
tap into it, and charge up the rovers with it.

|There is useful work for humans to do, such as examine rocks in a lab or
|repair vehicles.

Putting in a beacon on a communications tower is way up there on my
priority list. (That, and some seismometers that we sink into the
surface.)

|There is a risk that we'll spend twice as much for 30% more work.

Sure, but the more cargo we assemble in one place, the better. Getting
the communications tower up is extremely important, as is running
together one or more electrical powerlines.